git-apply: add --allow-empty flag
Some users or scripts will pipe "git diff" output to "git apply" when replaying diffs or commits. In these cases, they will rely on the return value of "git apply" to know whether the diff was applied successfully. However, for empty commits, "git apply" will fail. This complicates scripts since they have to either buffer the diff and check its length, or run diff again with "exit-code", essentially doing the diff twice. Add the "--allow-empty" flag to "git apply" which allows it to handle both empty diffs and empty commits created by "git format-patch --always" by doing nothing and returning 0. Add tests for both with and without --allow-empty. Signed-off-by: Jerry Zhang <jerry@skydio.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jerry Zhang committed
Dec 13, 2021 at 14:03 UTC
324eb77ee76277be99bdc54ef0b74ff30f5f567b
4 files changed
+30
-7
Documentation/git-apply.txt
+5
-1
index a32ad64718..b6d77f4206 100644
--- a/Documentation/git-apply.txt
+++ b/Documentation/git-apply.txt
@@ -16,7 +16,7 @@ SYNOPSIS
[--ignore-space-change | --ignore-whitespace]
[--whitespace=(nowarn|warn|fix|error|error-all)]
[--exclude=<path>] [--include=<path>] [--directory=<root>]
- [--verbose | --quiet] [--unsafe-paths] [<patch>...]
+ [--verbose | --quiet] [--unsafe-paths] [--allow-empty] [<patch>...]
DESCRIPTION
-----------
@@ -256,6 +256,10 @@ When `git apply` is used as a "better GNU patch", the user can pass
the `--unsafe-paths` option to override this safety check. This option
has no effect when `--index` or `--cached` is in use.
+--allow-empty::
+ Don't return error for patches containing no diff. This includes
+ empty patches and patches with commit text only.
+
CONFIGURATION
-------------
apply.c
+6
-2
index 0392f42066..fed195250b 100644
--- a/apply.c
+++ b/apply.c
@@ -4752,8 +4752,10 @@ static int apply_patch(struct apply_state *state,
}
if (!list && !skipped_patch) {
- error(_("unrecognized input"));
- res = -128;
+ if (!state->allow_empty) {
+ error(_("No valid patches in input (allow with \"--allow-empty\")"));
+ res = -128;
+ }
goto end;
}
@@ -5081,6 +5083,8 @@ int apply_parse_options(int argc, const char **argv,
OPT_CALLBACK(0, "directory", state, N_("root"),
N_("prepend <root> to all filenames"),
apply_option_parse_directory),
+ OPT_BOOL(0, "allow-empty", &state->allow_empty,
+ N_("don't return error for empty patches")),
OPT_END()
};
apply.h
+1
index da3d95fa50..16202da160 100644
--- a/apply.h
+++ b/apply.h
@@ -66,6 +66,7 @@ struct apply_state {
int threeway;
int unidiff_zero;
int unsafe_paths;
+ int allow_empty;
/* Other non boolean parameters */
struct repository *repo;
t/t4126-apply-empty.sh
+18
-4
index ceb6a79fe0..949e284d14 100755
--- a/t/t4126-apply-empty.sh
+++ b/t/t4126-apply-empty.sh
@@ -9,6 +9,8 @@ test_expect_success setup '
git add empty &&
test_tick &&
git commit -m initial &&
+ git commit --allow-empty -m "empty commit" &&
+ git format-patch --always HEAD~ >empty.patch &&
for i in a b c d e
do
echo $i
@@ -25,30 +27,42 @@ test_expect_success setup '
'
test_expect_success 'apply empty' '
- git reset --hard &&
rm -f missing &&
+ test_when_finished "git reset --hard" &&
git apply patch0 &&
test_cmp expect empty
'
+test_expect_success 'apply empty patch fails' '
+ test_when_finished "git reset --hard" &&
+ test_must_fail git apply empty.patch &&
+ test_must_fail git apply - </dev/null
+'
+
+test_expect_success 'apply with --allow-empty succeeds' '
+ test_when_finished "git reset --hard" &&
+ git apply --allow-empty empty.patch &&
+ git apply --allow-empty - </dev/null
+'
+
test_expect_success 'apply --index empty' '
- git reset --hard &&
rm -f missing &&
+ test_when_finished "git reset --hard" &&
git apply --index patch0 &&
test_cmp expect empty &&
git diff --exit-code
'
test_expect_success 'apply create' '
- git reset --hard &&
rm -f missing &&
+ test_when_finished "git reset --hard" &&
git apply patch1 &&
test_cmp expect missing
'
test_expect_success 'apply --index create' '
- git reset --hard &&
rm -f missing &&
+ test_when_finished "git reset --hard" &&
git apply --index patch1 &&
test_cmp expect missing &&
git diff --exit-code